A popular modification for existing motorcycles, including for example the Harley-Davidson Sportster® model, is the use of a wider rear tire. The reasons for the modification varies from rider to rider, and may include both aesthetic and functional aspects. The wider rear tire, for example, provides a smoother ride on a rigid or stiffly suspended frame, and tends to not follow rain grooves on the freeway as much as skinnier standard tires.
Of course, a wider rear tire generally displaces the wheel drive gear or sprocket laterally farther from the centerline of the wheel. Different schemes for accommodating a wider rear tire have been proposed. For example, in U.S. Pat. No. 5,996,718 to Desrosiers discloses a swing arm assembly that allows for the installation of an oversized rear wheel tire on a Harley-Davidson Softail™ motorcycle is disclosed. In U.S. Pat. No. 6,230,837 to Soileau, an improvement that allows for the front and rear tires to be aligned on the same centerline is disclosed, which appears to be intended for use with a single chain or drive belt connecting the transmission power take-off to the rear wheel. In U.S. Pat. No. 6,575,260 to Bourget, which is hereby incorporated by reference in its entirety, an intermediate jack shaft having two sprockets spaced apart by 2-4 inches, on one end of the shaft is disclosed. One chain connects one sprocket of the intermediate shaft to the transmission power take-off, and a second chain connects the other sprocket of the intermediate shaft to the rear wheel.